Plant protection agent

Abstract

A plant protection agent includes a photocatalyst particle including a titanium oxide compound. The surface of the photocatalyst particle is modified with a metal compound that includes a metal atom and a hydrocarbon group. The photocatalyst particle has absorption at a wavelength of 550 nm. The change in the absorbance of the photocatalyst particle at the wavelength of 550 nm which occurs when the photocatalyst particle is irradiated with white light having an illuminance of 3000 lux for 24 hours is 10% or more.

What is claimed is: 
     
         1 . A plant protection agent comprising:
 a photocatalyst particle including a titanium oxide compound, a surface of the photocatalyst particle being modified with a metal compound, the metal compound including a metal atom and a hydrocarbon group, the photocatalyst particle having absorption at a wavelength of 550 nm, a change in an absorbance of the photocatalyst particle at the wavelength of 550 nm which occurs when the photocatalyst particle is irradiated with white light having an illuminance of 3000 lux for 24 hours being 10% or more.   
     
     
         2 . The plant protection agent according to  claim 1 ,
 wherein the change in the absorbance of the photocatalyst particle at the wavelength of 550 nm is 20% or more.   
     
     
         3 . The plant protection agent according to  claim 1 ,
 wherein the change in the absorbance of the photocatalyst particle at the wavelength of 550 nm is 60% or less.   
     
     
         4 . The plant protection agent according to  claim 1 ,
 wherein the photocatalyst particle has absorption over an entire wavelength range of 500 to 600 nm.   
     
     
         5 . The plant protection agent according to  claim 1 ,
 wherein the ratio of the absorbance of the photocatalyst particle at a wavelength of 650 nm to the absorbance of the photocatalyst particle at the wavelength of 550 nm is less than 1.   
     
     
         6 . The plant protection agent according to  claim 1 ,
 wherein the photocatalyst particles have a volume-average size of 0.5 to 50 μm.   
     
     
         7 . The plant protection agent according to  claim 1 ,
 wherein the photocatalyst particle is formed by aggregation of primary particles, and   wherein the primary particles have an average size of 1 to 200 nm.   
     
     
         8 . The plant protection agent according to  claim 1 ,
 wherein the photocatalyst particles including the titanium oxide compound are one selected from the group consisting of titanium dioxide particles, metatitanic acid particles, titanium dioxide aerogel particles, and silica-titania composite aerogel particles.   
     
     
         9 . The plant protection agent according to  claim 1 ,
 wherein the metal atom is a silicon atom.   
     
     
         10 . The plant protection agent according to  claim 1 ,
 wherein the hydrocarbon group is a saturated or unsaturated aliphatic hydrocarbon group having 1 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms.   
     
     
         11 . The plant protection agent according to  claim 10 ,
 wherein the hydrocarbon group is a saturated or unsaturated aliphatic hydrocarbon group having 4 to 18 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms.   
     
     
         12 . The plant protection agent according to  claim 10 , wherein the hydrocarbon group is a saturated aliphatic hydrocarbon group. 
     
     
         13 . The plant protection agent according to  claim 1 ,
 wherein the metal compound is a metal compound including a metal atom and a hydrocarbon group directly bonded to the metal atom.   
     
     
         14 . The plant protection agent according to  claim 1 , further comprising an aqueous medium. 
     
     
         15 . The plant protection agent according to  claim 14 , wherein the aqueous medium includes water and a water-soluble organic solvent. 
     
     
         16 . The plant protection agent according to  claim 14 , wherein the ratio of the amount of the aqueous medium to the amount of the photocatalyst particle is 100:0.01 to 100:40 by mass. 
     
     
         17 . The plant protection agent according to  claim 14 , wherein the ratio of the amount of the aqueous medium to the amount of the photocatalyst particle is 100:0.01 to 100:20 by mass.